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diff --git a/openssl/doc/apps/smime.pod b/openssl/doc/apps/smime.pod new file mode 100644 index 000000000..caf2d2689 --- /dev/null +++ b/openssl/doc/apps/smime.pod @@ -0,0 +1,385 @@ +=pod + +=head1 NAME + +smime - S/MIME utility + +=head1 SYNOPSIS + +B<openssl> B<smime> +[B<-encrypt>] +[B<-decrypt>] +[B<-sign>] +[B<-verify>] +[B<-pk7out>] +[B<-des>] +[B<-des3>] +[B<-rc2-40>] +[B<-rc2-64>] +[B<-rc2-128>] +[B<-aes128>] +[B<-aes192>] +[B<-aes256>] +[B<-camellia128>] +[B<-camellia192>] +[B<-camellia256>] +[B<-in file>] +[B<-certfile file>] +[B<-signer file>] +[B<-recip file>] +[B<-inform SMIME|PEM|DER>] +[B<-passin arg>] +[B<-inkey file>] +[B<-out file>] +[B<-outform SMIME|PEM|DER>] +[B<-content file>] +[B<-to addr>] +[B<-from ad>] +[B<-subject s>] +[B<-text>] +[B<-rand file(s)>] +[cert.pem]... + +=head1 DESCRIPTION + +The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and +verify S/MIME messages. + +=head1 COMMAND OPTIONS + +There are five operation options that set the type of operation to be performed. +The meaning of the other options varies according to the operation type. + +=over 4 + +=item B<-encrypt> + +encrypt mail for the given recipient certificates. Input file is the message +to be encrypted. The output file is the encrypted mail in MIME format. + +=item B<-decrypt> + +decrypt mail using the supplied certificate and private key. Expects an +encrypted mail message in MIME format for the input file. The decrypted mail +is written to the output file. + +=item B<-sign> + +sign mail using the supplied certificate and private key. Input file is +the message to be signed. The signed message in MIME format is written +to the output file. + +=item B<-verify> + +verify signed mail. Expects a signed mail message on input and outputs +the signed data. Both clear text and opaque signing is supported. + +=item B<-pk7out> + +takes an input message and writes out a PEM encoded PKCS#7 structure. + +=item B<-in filename> + +the input message to be encrypted or signed or the MIME message to +be decrypted or verified. + +=item B<-inform SMIME|PEM|DER> + +this specifies the input format for the PKCS#7 structure. The default +is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER> +format change this to expect PEM and DER format PKCS#7 structures +instead. This currently only affects the input format of the PKCS#7 +structure, if no PKCS#7 structure is being input (for example with +B<-encrypt> or B<-sign>) this option has no effect. + +=item B<-out filename> + +the message text that has been decrypted or verified or the output MIME +format message that has been signed or verified. + +=item B<-outform SMIME|PEM|DER> + +this specifies the output format for the PKCS#7 structure. The default +is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER> +format change this to write PEM and DER format PKCS#7 structures +instead. This currently only affects the output format of the PKCS#7 +structure, if no PKCS#7 structure is being output (for example with +B<-verify> or B<-decrypt>) this option has no effect. + +=item B<-content filename> + +This specifies a file containing the detached content, this is only +useful with the B<-verify> command. This is only usable if the PKCS#7 +structure is using the detached signature form where the content is +not included. This option will override any content if the input format +is S/MIME and it uses the multipart/signed MIME content type. + +=item B<-text> + +this option adds plain text (text/plain) MIME headers to the supplied +message if encrypting or signing. If decrypting or verifying it strips +off text headers: if the decrypted or verified message is not of MIME +type text/plain then an error occurs. + +=item B<-CAfile file> + +a file containing trusted CA certificates, only used with B<-verify>. + +=item B<-CApath dir> + +a directory containing trusted CA certificates, only used with +B<-verify>. This directory must be a standard certificate directory: that +is a hash of each subject name (using B<x509 -hash>) should be linked +to each certificate. + +=item B<-des -des3 -rc2-40 -rc2-64 -rc2-128 -aes128 -aes192 -aes256 -camellia128 -camellia192 -camellia256> + +the encryption algorithm to use. DES (56 bits), triple DES (168 bits), +40, 64 or 128 bit RC2, 128, 192 or 256 bit AES, or 128, 192 or 256 bit Camellia respectively. If not +specified 40 bit RC2 is used. Only used with B<-encrypt>. + +=item B<-nointern> + +when verifying a message normally certificates (if any) included in +the message are searched for the signing certificate. With this option +only the certificates specified in the B<-certfile> option are used. +The supplied certificates can still be used as untrusted CAs however. + +=item B<-noverify> + +do not verify the signers certificate of a signed message. + +=item B<-nochain> + +do not do chain verification of signers certificates: that is don't +use the certificates in the signed message as untrusted CAs. + +=item B<-nosigs> + +don't try to verify the signatures on the message. + +=item B<-nocerts> + +when signing a message the signer's certificate is normally included +with this option it is excluded. This will reduce the size of the +signed message but the verifier must have a copy of the signers certificate +available locally (passed using the B<-certfile> option for example). + +=item B<-noattr> + +normally when a message is signed a set of attributes are included which +include the signing time and supported symmetric algorithms. With this +option they are not included. + +=item B<-binary> + +normally the input message is converted to "canonical" format which is +effectively using CR and LF as end of line: as required by the S/MIME +specification. When this option is present no translation occurs. This +is useful when handling binary data which may not be in MIME format. + +=item B<-nodetach> + +when signing a message use opaque signing: this form is more resistant +to translation by mail relays but it cannot be read by mail agents that +do not support S/MIME. Without this option cleartext signing with +the MIME type multipart/signed is used. + +=item B<-certfile file> + +allows additional certificates to be specified. When signing these will +be included with the message. When verifying these will be searched for +the signers certificates. The certificates should be in PEM format. + +=item B<-signer file> + +the signers certificate when signing a message. If a message is +being verified then the signers certificates will be written to this +file if the verification was successful. + +=item B<-recip file> + +the recipients certificate when decrypting a message. This certificate +must match one of the recipients of the message or an error occurs. + +=item B<-inkey file> + +the private key to use when signing or decrypting. This must match the +corresponding certificate. If this option is not specified then the +private key must be included in the certificate file specified with +the B<-recip> or B<-signer> file. + +=item B<-passin arg> + +the private key password source. For more information about the format of B<arg> +see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. + +=item B<-rand file(s)> + +a file or files containing random data used to seed the random number +generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). +Multiple files can be specified separated by a OS-dependent character. +The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for +all others. + +=item B<cert.pem...> + +one or more certificates of message recipients: used when encrypting +a message. + +=item B<-to, -from, -subject> + +the relevant mail headers. These are included outside the signed +portion of a message so they may be included manually. If signing +then many S/MIME mail clients check the signers certificate's email +address matches that specified in the From: address. + +=back + +=head1 NOTES + +The MIME message must be sent without any blank lines between the +headers and the output. Some mail programs will automatically add +a blank line. Piping the mail directly to sendmail is one way to +achieve the correct format. + +The supplied message to be signed or encrypted must include the +necessary MIME headers or many S/MIME clients wont display it +properly (if at all). You can use the B<-text> option to automatically +add plain text headers. + +A "signed and encrypted" message is one where a signed message is +then encrypted. This can be produced by encrypting an already signed +message: see the examples section. + +This version of the program only allows one signer per message but it +will verify multiple signers on received messages. Some S/MIME clients +choke if a message contains multiple signers. It is possible to sign +messages "in parallel" by signing an already signed message. + +The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME +clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7 +encrypted data is used for other purposes. + +=head1 EXIT CODES + +=over 4 + +=item 0 + +the operation was completely successfully. + +=item 1 + +an error occurred parsing the command options. + +=item 2 + +one of the input files could not be read. + +=item 3 + +an error occurred creating the PKCS#7 file or when reading the MIME +message. + +=item 4 + +an error occurred decrypting or verifying the message. + +=item 5 + +the message was verified correctly but an error occurred writing out +the signers certificates. + +=back + +=head1 EXAMPLES + +Create a cleartext signed message: + + openssl smime -sign -in message.txt -text -out mail.msg \ + -signer mycert.pem + +Create and opaque signed message + + openssl smime -sign -in message.txt -text -out mail.msg -nodetach \ + -signer mycert.pem + +Create a signed message, include some additional certificates and +read the private key from another file: + + openssl smime -sign -in in.txt -text -out mail.msg \ + -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem + +Send a signed message under Unix directly to sendmail, including headers: + + openssl smime -sign -in in.txt -text -signer mycert.pem \ + -from steve@openssl.org -to someone@somewhere \ + -subject "Signed message" | sendmail someone@somewhere + +Verify a message and extract the signer's certificate if successful: + + openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt + +Send encrypted mail using triple DES: + + openssl smime -encrypt -in in.txt -from steve@openssl.org \ + -to someone@somewhere -subject "Encrypted message" \ + -des3 user.pem -out mail.msg + +Sign and encrypt mail: + + openssl smime -sign -in ml.txt -signer my.pem -text \ + | openssl smime -encrypt -out mail.msg \ + -from steve@openssl.org -to someone@somewhere \ + -subject "Signed and Encrypted message" -des3 user.pem + +Note: the encryption command does not include the B<-text> option because the message +being encrypted already has MIME headers. + +Decrypt mail: + + openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem + +The output from Netscape form signing is a PKCS#7 structure with the +detached signature format. You can use this program to verify the +signature by line wrapping the base64 encoded structure and surrounding +it with: + + -----BEGIN PKCS7----- + -----END PKCS7----- + +and using the command, + + openssl smime -verify -inform PEM -in signature.pem -content content.txt + +alternatively you can base64 decode the signature and use + + openssl smime -verify -inform DER -in signature.der -content content.txt + +Create an encrypted message using 128 bit Camellia: + + openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem + +=head1 BUGS + +The MIME parser isn't very clever: it seems to handle most messages that I've thrown +at it but it may choke on others. + +The code currently will only write out the signer's certificate to a file: if the +signer has a separate encryption certificate this must be manually extracted. There +should be some heuristic that determines the correct encryption certificate. + +Ideally a database should be maintained of a certificates for each email address. + +The code doesn't currently take note of the permitted symmetric encryption +algorithms as supplied in the SMIMECapabilities signed attribute. this means the +user has to manually include the correct encryption algorithm. It should store +the list of permitted ciphers in a database and only use those. + +No revocation checking is done on the signer's certificate. + +The current code can only handle S/MIME v2 messages, the more complex S/MIME v3 +structures may cause parsing errors. + +=cut |